Giratina with the wrong forme's stats. - Page 1
If you have giratina in a box, then give griseous orb to/take away the griseous orb from giratina, And then, before doing anything else, Put the giratina in your party using the move pokemon option, and then get out of the PC.
The giratina will have the other forme's stats. This may work with shaymin, but I am not for sure.
I haven't tried this with Platinum(It works with HG though)
It doesn't seem to work for me. I take away the Griseous Orb from Giratina and it still has the usual stats for its altered from, it doesn't seem to work when I give it the Griseous Orb either. (Platinum)
If this works on HG/SS Nintendo probably didn't look into the object as much, because the item still unequips itself in trade and you have to get one from a Giratina that Arceus has made and so Nintendo possibly missed this out.
Doesn't work for me on Platinum either.